AP Statistics: Part 1 Exam Breakdown
Exam breakdown: Chapters 1-6
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Day 1
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Day 2
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o
(Wednesday, October 8th)
Ten Multiple Choice Questions
Five Short Answer Questions
(Thursday, October 9th)
2 AP Multiple Choice Questions
2 AP Free Response Questions
Topics to be reviewed:
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Variables:
o Categorical
 Bar graphs: work well for comparing counts
 Tables: work to summarize data using either counts or relative
freq.
 Pie charts: display divisions of a whole
 Segmented bar charts: display divisions of a whole
 Look for associations by comparing marginal and conditional
distributions between variables
o Quantitative
 Histograms: good way to see the distribution
 Stem-and-leafs: great when working by hand, and with small data
sets
 Boxplots: best when comparing several distributions
 Dotplots: used as an alternative to a histogram when collecting
data
 Timeplots: show trends over time
 Describe data in terms of center, shape, and spread, as well as
any unusual features
 Shape: Uniform, unimodal, bimodal, multimodal
 IF unimodal, then: symmetric or skew
 If severely skew, may benefit from re-expressing (log or sq.
rt.)
 5-number summary: Min, Q1, Median, Q3, Max
 Use mean and standard deviation if: Unimodal and symmetric
Normal Distributions
o Shifting a distribution by adding or subtracting a constant affects
measures of position, but not measures of spread
o Rescaling by multiplying or dividing affects both
o Use rule of thumb: 68-95-99.7
o Normal percentile tables can be used as models to provide
approximations about a sample if that sample fits closely…
(if it is approximately perfect… histogram is unimodal and symmetric or
normal probability plot is nearly straight and diagonal)
Example Multiple Choice Questions
1. The SPCA collects the following data about the dogs they house. Which is
categorical?
a. Breed
Age
Weight
Number of days housed
Veterinary costs
Which of those variables about German Shepherds is most likely to be described by
a Normal model?
a. Breed
b. Age
c. Weight
d. Number of days housed
e. Veterinary costs
The SPCA has kept these data records for the past 20 years. If they want to show a
trend in the number of dogs they have housed, what kind of plot should they make?
a. Boxplot
b. Timeplot
c. Bar graph
d. Pie chart
e. Histogram
Last weekend police ticketed 18 men whose mean speed was 72 miles per hour,
and 30 women going an average of 64 mph. Overall, what was the mean speed of
all the people ticketed?
a. 67 mph
b. 68 mph
c. 69 mph
d. None of those
e. It cannot be determined
Which is true of the data shown in the histogram on the right?
I. The distribution is skewed to the right.
II. The mean is probably smaller than the median.
III. We should use median and IQR to summarize these data.
a. I only
b. II only
c. III only
d. II and III only
e. I, II, and III
What is the best estimate of the standard deviation of
men’s’ weights displayed in the dotplot below?
a. 10
b. 15
c. 25
d. 35
e. 40
b.
c.
d.
e.
2.
3.
4.
5.
6.
7. If we want to discuss any gaps and clusters in a data set, which of the following
should not be chosen to display the data set?
a. Histogram
b. Stem-and-leaf plot
c. Boxplot
d. Dotplot
e. Any of these would work
8. Suppose a Normal model describes the number of pages that printer ink cartridges
will last. If we keep track of printed pages for the 47 printers at a company’s office,
which must be true?
I. The page counts for those ink cartridges will be normally distributed.
II. The histogram for those pages counts will be symmetric.
III. 95% of those page counts will be within 2 standard deviations of the mean.
a. None
b. I only
c. II only
d. II and III
e. I, II, and III
9. Suppose that a Normal model describes fuel economy (miles per gallon) for
automobiles and that a Saturn has a standardized score (z-score) of +2.2. This
means that Saturns…
a. Get 2.2 miles per gallon
b. Get 2.2 times the gas mileage of the average car
c. Get 2.2 mpg more than the average car
d. Have a standard deviation of 2.2 mpg
e. Achieve fuel economy that is 2.2 standard deviations better than
the average car
Example Short Answer Questions
1. The table on the right shows how a company’s
employees commute to work.
a. What is the marginal distribution (in %)
of mode of transportation?
Car _______ Bus _______ Train _______
b. What is the conditional distribution (in %) of mode of transportation for
management?
Car _______ Bus _______ Train _______
c. What kind of display would you use to show the association between job
class and mode of transportation? (Just name a graph.)
____________________________________
d. Do job classification and mode of transportation appear to be
independent? Give statistical evidence to support your conclusion.
2. A publishing company pays its sales staff $600 a week plus a commission of $0.50
per book sold. For example, a salesman who sold 440 books earned
600 + .50(440) = $820.
Book Sold
$ Earned
a. The table shows summary
Mean
640
statistics for the number of
Standard
books the large sales staff
360
Deviation
sold last week. Fill in the table
IQR
450
to show the statistics for the
pay these people earned.
Maximum
1420
b. The newest employee had a
pretty good week. Among all the salespeople, her pay corresponded to a
z-score of +1.80. What was the z-score of the number of books she sold?
3. In their October 2003 issue, Consumer Reports evaluated the price and
performance of 23 models of cordless phones. Computer output gives these
summaries for the prices:
a. Were any of the prices outliers? Explain how you made your decision.
b. One of the manufacturers advertises a cordless phone “economy priced at
only $31.95”. Would you consider that to be a very low price? Explain.
4. Owners of an exercise gym believe that a Normal model is useful in projecting the
number of clients who will exercise in their gym each week. They use a mean of
800 clients and a standard deviation of 90 clients.
a. Draw and clearly label the normal model.
b. What is the first quartile of the weekly number of clients? (Show work)
___________________
c. An owner of another gym reports that 5% of the time their gym has fewer
than 450 clients and 40% of the time the gym has more than 1085
clients. What parameters should that owner use for his Normal model?
N(__________, __________)
5. A roadway construction process uses a machine that pours concrete onto the
roadway and measures the thickness of the concrete so the roadway will measure
up to the required depth in inches. The concrete thickness needs to be consistent
across the road, but the machine isn’t perfect and it is costly to operate. Since
there’s a safety hazard if the roadway is thinner than the minimum 23-inch
thickness, the company sets the machine to average 26 inches for the batches of
concrete. The company’s statistician believes the thickness level of the machine’s
concrete output can be described by a Normal model with a standard deviation of
1.75 inches.
a. What percent of the concrete roadway is under the minimum depth?
_________________
b. The company’s lawyers insist to them that no more than 3% of the output
be under the limit. Because of the expense of operating the machine,
they cannot afford to reset the mean to a higher value. Instead they will
try to reduce the standard deviation to achieve the “only 3% under
minimum” goal. What standard deviation must they attain?
__________________
c. Explain what achieving a smaller standard deviation means in this
context.
Part I Review Book Problems
Page 135-143 in your textbook contains the Part I Review problems. The complete
solutions to ALL of these problems can be found under the “Part I” tab on the class
website: www.myhaikuclass.com/hjhunt/apstats. It is on the side of the page called
“Part I Review Book Solutions”. Here is a breakdown of the problems and what content
each covers. Please focus on the material that you feel you need the most help/practice
in. It’s a good idea to hit each concept but to practice the content you struggle most
with, even more.
AP Questions
Please refer to the FRAPPY packet from last week with 6 free response questions to
study for that portion of the test. The complete solutions to these free response
questions is also located on the class website under the “AP Practice” tab on the left
side of the website. If you know the content for chapters 1-6 and can write in context
and in full sentences, you will be fine on the AP free response questions. The AP
multiple choice questions are similar to the multiple choice questions provided on
previous pages as well.
Example Multiple Choice Questions – Solutions
1) A 2) C 3) B 4) A 5) D 6) C 7) C 8) A 9) E